By SHARON UDASIN
01/19/2012 03:43

Newly found sediments reveal information about ancient climactic conditions both in Dead Sea region, Sahara.
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An international drilling research project that occurred in the Dead Sea last year has revealed that about 125,000 years ago, the waters had dried up almost entirely as a result of climate change.

The drilling, which took place in November 2010 and March 2011, occurred through the International Continental Drilling Program (ICDP), under the direction of Prof. Mordechai Stein of the Geological Survey of Israel and the Hebrew University as well as Prof. Zvi Ben-Avraham of Tel Aviv University, with support from the Israel Academy of Sciences and Humanities.

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Drilling 300 meters down in the center of the sea, as well as off the shores of Ein Gedi, the newly found sediments have revealed information about ancient climactic conditions both in the Dead Sea region and in areas as far as the Arabian and Sahara deserts, according to the researchers.

“We think that the Dead Sea is a key locality to reconstruct and establish the variations of the regional climate of this area of the Mediterranean,” Stein told The Jerusalem Post, noting that by having this information, scientists can model the effects of global warming for the future.

In a preliminary analysis of the cores uncovered from depths of 250 meters below the lake’s floor, the researchers found thick sequences of salt covered by rock pebbles, which revealed a period in which the lake had almost entirely dried up. In periods of time where freshwater was flowing into the sea, the watershed brought with it two ingredients: sediments and calcium carbonate, Stein explained. During more arid periods, however, the water’s recession left the area with saturated salt deposits as the liquid evaporated – hence the 45-meter layer of salt that the scientists discovered, according to Stein.

“In order to deposit such a thick sequence of salt, the conditions in the drainage area were very arid – there was no supply of freshwater,” he said. “Then the layer of pebbles on top of the salt tells us that the shorelines were not far away.”

The findings uncovered in the drilling project should serve as a warning for the condition – and potential future drying – of today’s Dead Sea, which is 426 meters below sea level and continually sinking, according to the researchers.

While in the past, natural climate change was able to eventually refill the Dead Sea’s basin, this can no longer happen today, as the Jordan River no longer provides water to the basin and instead furnishes the needs of the countries surrounding it, the study said.

“What is happening now is that Israel, Jordan and Syria are not letting the freshwater run into the Dead Sea anymore because we use it in our lives,” Stein added.

Environmental advocates stressed the importance of the study’s findings, noting that much more must be done to help conserve the waters of the Dead Sea.

“The level of the Dead Sea has changed throughout history.

There were periods when the level was lower and there were periods when the level was significantly higher,” Amit Bracha, the executive director of Adam Teva V’Din (Israel Union for Environmental Defense) told the Post.

“However, the current decline of the Dead Sea level is clearly due to human intervention. Changes in the water sector and the Dead Sea Works are responsible for about 20% of the drop in the level. Therefore, the state and enterprises must bear responsibility for the damages and take immediate action in order to stop the damage and rehabilitate the region.”

Gidon Bromberg, the Israel director for Friends of Earth Middle East, echoed Bracha’s sentiments, adding, “The warning for the future from the new scientific study is that the present tragedy facing the Dead Sea is all a man-made disaster, completely different from the past where the Dead Sea was always able to fully recover when wet rainy years returned.”

Israel, Syria and Jordan are capturing nearly all of the rain that falls in the region, and both Israel and Jordan are extracting minerals through evaporation ponds – processes that must be legislated more effectively, according to Bromberg.

While Stein said that he and his team members are using their project primarily for scientific reasons – to map climate changes over time – he did warn that there is a social lesson to be learned from the findings as well.

“There were episodes when the aridity was so large that the Dead Sea could shrink extensively, but it came back because of the natural system,” Stein said.

“Today the drop in the Dead Sea is basically an anthropogenic one.”

http://www.jpost.com/Sci-Tech/Article.aspx?id=254249